Greater Sage-Grouse Centrocercus urophasianus – Status: Endangered; ESA Candidate
Greater Sage-grouse—female — (left) and male (above)
Population status: Once numbered an estimated 16 million, now 200,000 to 500,000 individuals.
Figure 1. Greater Sage-Grouse densities from US DOI
(Doherty et al. 2010).
- Ecological-Key indicator of intact sage-steppe systems with healthy riparian areas
- Pest control- Primary diet of forbs and insects
- Economic- A favorite of hunters, tourists, and photographers
- Aesthetic/cultural- Important to many Westerners, especially ranchers and native/First Nations groups
- Historical- Described in 1805 by Lewis & Clark; “as western as a Stetson hat and sagebrush” –J. K. Terres
Names through history:
- Cock of the plains (by M. Lewis 1805);
- Sage hen;
- Named Greater Sage-Grouse in 2000 to differentiate from the Gunnison Sage-Grouse of Colorado and Utah.
Weighing 3-6 pounds, with males larger than females, this is the largest grouse species in North America.
- Loss and degradation of habitat, including roads, vertical structures (power lines, fences, etc.), and unnatural noise
- Raven populations subsidized by human activities
- West Nile Virus
Conservation needs: Sage grouse are a relatively wide-ranging or “landscape species.” This means that because they depend upon several habitats (sage, bare, grass, riparian) within a landscape that their presence may be used as an indication of the health of a landscape. The sage grouse life cycle is anchored to specific lek sites where dancing males work collectively to attract hens, though ultimately few males per lek actually mate in a given year. Hens nest within 3-5 km of lek sites and most (76%) males remain within 1km of the leks. Hens will not change leks visited year after year even if the number of males has declined severely. Having evolved on the sage-steppe plains, sage grouse are sensitive to large vertical structures and disturbances associated with energy extraction activities. The northern populations migrate 75mi (120km) south to wintering areas with less snow cover and greater food availability.
Figure 1. Greater Sage-Grouse distribution from USGS (Aldridge et al. 2008).
Using data from 50 studies of demographic rates, range-wide and from 1938 to 2011, Taylor et al. (2012) assessed the relative importance of different life stages to maintaining Greater Sage-Grouse populations. Based on their work, they recommend that management efforts focus on increasing female survival by restoring large, intact sagebrush-steppe landscapes, reducing persistent sources of human-caused mortality, and eliminating anthropogenic habitat features that subsidize species that prey on females. Their analysis also supports efforts to increase chick survival and nest success by eliminating anthropogenic habitat features that subsidize predators of nests and young, and by managing shrub, forb, and grass cover, height, and composition to meet local brood-rearing and nesting habitat guidelines. In terms of common predators, Common Ravens have been identified as predators of eggs and their presence correlated with human activities and related structures used as nest sites and perches, e.g., near towns, power line poles, etc. (Bui et al. 2010). Grazing by large ungulates, such as cattle, is an important management tool for refining habitat when managed appropriately for local conditions–livestock presence has been shown to benefit nesting and brood-rearing sage-grouse (Foster et al. 2013). West Nile Virus can have population impacts similar in magnitude to those from oil well densities alone, however, the two processes combined multiply impacts with up to 4 times the predicted inactivity at leks (Taylor et al. 2013).
Dechant et al. (2003) identified the following needs for Greater Sage-Grouse:
- Native sagebrush habitats have undergone drastic declines in the last century, with concomitant declines in populations of sage grouse. Maintain, conserve, and restore large blocks of intact sagebrush with a healthy understory of native grasses and forbs.
- Protect lek sites and adjacent habitat (up to 18 km from the lek, depending on migratory status of the population) from alteration, such as burning, spraying, or oil and gas development.
- During spring, manage breeding habitats to maintain sagebrush canopy cover of 15 to 25% and perennial herbaceous cover of ≥15% grasses or ≥10% forbs; grasses and forbs should be ≥18 cm tall.
- Control encroachment of pinyon/juniper woodlands into sagebrush habitats. Such encroachment eventually eliminates sagebrush habitat in the understory. Management practices to control pinyon/juniper must be tailored to local conditions, such as soils, sagebrush taxa present, presence of other species of concern, and available moisture.
- Identify and attempt to eliminate or control invasive, non-native plants in sagebrush steppe. The displacement of native sagebrush steppe by cheatgrass is widespread and restoration will require unprecedented resources.
Relationship to livestock grazing and other land uses
Manage livestock grazing through stocking rates and season of use on all seasonal ranges of sage-grouse to avoid habitat degradation. In nesting and brood-rearing habitats, ensure that grazing does not reduce herbaceous understory cover below levels that serve as a deterrent to potential predators of eggs and chicks. Healthy native understories also support insects and forbs that are important in diets of pre-laying hens and chicks. Riparian areas and wet meadows used for brood rearing are especially sensitive to grazing by livestock; in these habitats, removal of livestock before the nesting season is prudent.
Avoid application of herbicides or pesticides in sage-grouse habitats, particularly during nesting or brood-rearing periods. Sage-grouse feed on insects during spring and summer, and chicks rely heavily on insects during the first few weeks of life.
Developments related to mining, oil/gas extraction, and other purposes directly eliminate habitat (e.g., through road-building, construction of settling ponds, and surface disturbance), fragment sagebrush communities, and increase disturbance from vehicles and other associated activities. Power lines, especially within 3 km of seasonal habitats can increase predation of sage-grouse from increased availability of perches for roosting and nesting by raptors.
The Sage Grouse Initiative http://www.sagegrouseinitiative.com/ is a cooperative interagency effort that offers technical expertise and resources to livestock producers for sage grouse recovery.
Sage-Grouse populations typically inhabit large, unbroken expanses of sagebrush. Distances moved by females from leks to nests in central Montana were similar between age classes, with adults moving 2.5 km, and yearlings 2.8 km. Home ranges of hens vary widely among individuals and seasons. In eastern Idaho, home ranges of 28 hens during summer averaged 285 ha but varied widely, from 9 to 710 ha. Sagebrush patches used by broods averaged 86 ha in June and July in central Montana but diminished to 52 ha later in August and September.
Bui, T. D., J. M. Marzluff, and B. Bedrosian. 2010. Common Raven Activity in Relation to Land Use in Western Wyoming: Implications for Greater Sage-Grouse Reproductive Success. Condor 112:65-78.
Dechant, J. A., M. L. Sondreal, D. H. Johnson, L. D. Igl, C. M. Goldade, P. A. Rabie, and B. R. Euliss. 2003. Effects of management practices on grassland birds: Greater Sage-grouse. Northern Prairie Wildlife Research Center, Jamestown, ND. N. Prairie Wildlife Res. Center Online. https://pubs.er.usgs.gov/publication/70159591 (Version 12AUG2004)
Foster, M.A., J.T. Ensign, W.N. Davis & D.C. Tribby. 2013. Greater Sage-Grouse in the southeast Montana sage-grouse core area. Montana Fish, Wildlife and Parks in partnership with U.S. Dept. of the Interior, Bureau of Land Management. 108 p. http://fwp.mt.gov/fwpDoc.html?id=62566
Taylor, R.L., B. L. Walker, D. E. Naugle, L. S. Mills. 2012. Managing multiple vital rates to maximize greater sage-grouse population growth. Journal of Wildlife Management 76:336-347. doi: 10.1002/jwmg.267
Taylor, R. L., J. D. Tack, D. E. Naugle, L. S. Mills. 2013. Combined Effects of Energy Development and Disease on Greater Sage-Grouse. PLoS ONE 8:e71256. doi:10.1371/journal.pone.0071256
Conservation Plans/Other sources:
Sage Grouse Initiative — Wildlife Conservation Through Sustainable Ranching. sagegrouseinitiative.com
Alberta Wilderness Association — Sage Grouse Partnership of landowners, agencies, and interested parties http://albertawilderness.ca/issues/wildlife/sage-grouse
Western Governors’ Crucial Habitat Assessment Tool — Mapping Fish and Wildlife across the West